A new study has come to some conclusions that are bound to be a shock to millions of people when it comes to attention deficit hyperactivity disorder (ADHD).

The study found that ADHD is vastly over-diagnosed and in a large percentage of cases, parents are simply frustrated with the immaturity of the children, according to a Elsevier Health Services statement.

ADHD involves a number of behavior problems, including poor attention span, restlessness, and low concentration. The number of children diagnosed with ADHD is massive — in Britain, about 400,000 children have been prescribed drugs to deal with the issue. Prescriptions of Ritalin, an ADHD drug, have doubled to 922,000 per year for ADHD children.

But ADHD medication has its own side effects, including weight loss, liver problems, or even suicidal thoughts, so it should not be prescribed lightly.

A study of 400,000 children between four and 17 years of age in Taiwan found that ADHD diagnoses change significantly depending on in which month they were born, as 2.8 percent of boys born in September — the start of the school year — had ADHD compared to 4.5 percent for those born in August, and that the figure rises steadily over the school year. This seems to suggest that as teachers compare their behavior to more mature children, some of whom may be older, ADHD behavior becomes the default explanation for restlessness.

“Our findings emphasize the importance of considering the age of a child within a grade when diagnosing ADHD and prescribing medication to treat ADHD,” Dr. Mu-Hong Chen said in the statement.